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Questions and Answers
What is the primary function of the axon in a neuron?
What is the primary function of the axon in a neuron?
What are axon collaterals?
What are axon collaterals?
What is the axon hillock?
What is the axon hillock?
What is the role of the myelin sheath?
What is the role of the myelin sheath?
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Which part of the neuron contains the nucleus?
Which part of the neuron contains the nucleus?
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What is the primary type of cell from which brain tumors can often arise?
What is the primary type of cell from which brain tumors can often arise?
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Which component primarily forms the myelin sheath in the central nervous system (CNS)?
Which component primarily forms the myelin sheath in the central nervous system (CNS)?
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What challenge does the blood-brain barrier pose for treating gliomas?
What challenge does the blood-brain barrier pose for treating gliomas?
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What is a characteristic feature of mature neurons regarding cell division?
What is a characteristic feature of mature neurons regarding cell division?
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What is the composition of the myelin sheath?
What is the composition of the myelin sheath?
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What function do sensory neurons perform in the nervous system?
What function do sensory neurons perform in the nervous system?
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Which neuron type is confined solely to the central nervous system?
Which neuron type is confined solely to the central nervous system?
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What is the role of the soma in a neuron?
What is the role of the soma in a neuron?
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What is the primary function of dendrites in a neuron?
What is the primary function of dendrites in a neuron?
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Which component is responsible for the initial segment of a neuron's axon?
Which component is responsible for the initial segment of a neuron's axon?
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What is contained within the cytoplasm of the soma?
What is contained within the cytoplasm of the soma?
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How do dendrites enhance a neuron's ability to process information?
How do dendrites enhance a neuron's ability to process information?
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What is the function of the myelin sheath?
What is the function of the myelin sheath?
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Which part of the neuron is responsible for integrating incoming signals?
Which part of the neuron is responsible for integrating incoming signals?
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Which structure is responsible for the direction of signal transmission in a neuron?
Which structure is responsible for the direction of signal transmission in a neuron?
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What is the role of the axon in a neuron?
What is the role of the axon in a neuron?
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What component of a neuron is responsible for its structural integrity?
What component of a neuron is responsible for its structural integrity?
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What can be inferred about the relationship between the number of dendrites and a neuron's information processing capacity?
What can be inferred about the relationship between the number of dendrites and a neuron's information processing capacity?
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What structural feature of dendrites resembles tree branches in winter?
What structural feature of dendrites resembles tree branches in winter?
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Which part of a neuron is involved in the initial reception of signals?
Which part of a neuron is involved in the initial reception of signals?
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What is the significance of the myelin sheath in neural transmission?
What is the significance of the myelin sheath in neural transmission?
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What is the primary function of sensory (afferent) neurons?
What is the primary function of sensory (afferent) neurons?
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Which of the following divisions is part of the peripheral nervous system?
Which of the following divisions is part of the peripheral nervous system?
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What type of neuron is involved in the integrative function within the CNS?
What type of neuron is involved in the integrative function within the CNS?
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Which property of neurons allows them to respond to environmental changes?
Which property of neurons allows them to respond to environmental changes?
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What is the role of motor (efferent) neurons?
What is the role of motor (efferent) neurons?
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Which subdivision of the nervous system is responsible for the sympathetic division?
Which subdivision of the nervous system is responsible for the sympathetic division?
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What is commonly secreted at the end of a nerve fiber when an electrical signal reaches it?
What is commonly secreted at the end of a nerve fiber when an electrical signal reaches it?
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Which type of division in the nervous system is responsible for voluntary motor control?
Which type of division in the nervous system is responsible for voluntary motor control?
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What is the primary function of the synaptic knob?
What is the primary function of the synaptic knob?
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What is the main distinguishing feature of an axon compared to other neuron structures?
What is the main distinguishing feature of an axon compared to other neuron structures?
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What do Schwann cells contribute to the axon?
What do Schwann cells contribute to the axon?
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Which part of the axon is responsible for initiating the action potential?
Which part of the axon is responsible for initiating the action potential?
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Which structure is NOT part of the axon?
Which structure is NOT part of the axon?
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What are the gaps between myelin sheaths called?
What are the gaps between myelin sheaths called?
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What is axoplasm?
What is axoplasm?
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Which component of the neuron is directly involved in the transmission of electrical signals?
Which component of the neuron is directly involved in the transmission of electrical signals?
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Study Notes
Nervous Tissue Overview
- The nervous system is complex and fundamental to conscious experience, personality, and behavior
- It coordinates with the endocrine system
- Endocrine system communicates via chemical messengers (hormones) released into the bloodstream
- Nervous system uses electrical and chemical signals to transmit messages between cells
Nervous System Tasks
- Sense organs gather and transmit information to the spinal cord and brain
- The brain and spinal cord process this information, recalling past experiences to determine the appropriate response
- The brain and spinal cord command muscles and glands to execute the response
Nervous System Subdivisions
-
Central Nervous System (CNS):
- Brain and spinal cord
- Enclosed in bony coverings (cranium and vertebral column)
-
Peripheral Nervous System (PNS):
- All nervous system components outside the brain and spinal cord
- Contains:
- Nerves: Bundles of nerve fibers (axons) with connective tissue
- Ganglia: Knot-like swellings in nerves containing neuron cell bodies
Peripheral Nervous System Subdivisions (Functional)
-
Sensory (Afferent) Division:
- Carries sensory signals from various receptors to the CNS
- Includes:
- Somatic Sensory Division: Skin, muscles, bones, and joints
- Visceral Sensory Division: Internal organs (heart, lungs, stomach, bladder)
-
Motor (Efferent) Division: Carries signals from CNS to effectors that carry out the response
- Includes:
- Somatic Motor Division: Skeletal muscles (voluntary movements and reflexes)
-
Visceral Motor Division (Autonomic Nervous System):
- Sympathetic Division: Prepares the body for action (accelerates heart rate, respiration)
- Parasympathetic Division: Calming effect (slows heart rate, stimulates digestion and urination)
- Includes:
Universal Neuron Properties
- Excitability (Irritability) : Responds to stimuli
- Conductivity: Carries electrical signals
- Secretion: Releases chemical neurotransmitters to stimulate next cells
Neuron Functional Classes
- Sensory (Afferent) neurons: Detect stimuli and transmit signals to the CNS
- Interneurons (Association neurons): Located entirely within the CNS, process, store, and retrieve information, and make decisions about how the body should respond to stimuli
- Motor (Efferent) neurons: Transmit signals from the CNS to muscles and glands (effectors)
Neuron Structure
- Soma (Neurosoma, Cell Body): Control center, contains nucleus and other organelles
- Dendrites: Receive signals from other neurons
- Axon (Nerve Fiber): Carries signals away from the soma
- Axon Collaterals: Branches of axons
- Synaptic Knobs (Terminal Buttons): Form synapses with the next cell and release neurotransmitters
-
Myelin Sheath: Insulating layer around some axons for faster signal transmission
- Formed by oligodendrocytes in CNS and Schwann cells in PNS
- Consists of 20% protein and 80% lipid
- Nodes of Ranvier and internodes are segmented sections
Neuron Classification
- Multipolar: Most common; many dendrites, one axon (brain and spinal cord)
- Bipolar: One axon, one dendrite (olfactory cells, retina, inner ear)
- Unipolar: One process leading away from the soma (sensory neurons); from skin/organs to spinal cord
- Anaxonic: Many dendrites, no axon (in the brain)
Support Cells (Neuroglia)
- Outnumber neurons in the nervous system.
- Provide structural support and protection
- Types include:
- Oligodendrocytes: Form myelin sheaths in CNS
- Ependymal Cells: Line brain cavities, secrete and circulate cerebrospinal fluid (CSF)
- Microglia: Small macrophages that remove cellular debris
- Astrocytes: Most abundant, form framework, stimulate blood-brain barrier formation, convert glucose to lactate, and provide nourishment to neurons
- Schwann Cells: Form myelin sheaths in PNS; assist in fiber regeneration
- Satellite Cells: Surround somas in ganglia, regulate chemical environment
Myelin
- Insulating layer around some axons
- Speeds signal transmission
Diseases of the Myelin Sheath
- Multiple Sclerosis: Degradation of myelin in the CNS
Glial Cells and Brain Tumors
- Tumors: Masses of rapidly dividing cells
- Brain Tumors: Arise from meninges, metastasis from other organs, or glial cells
- Gliomas: Rapidly growing, highly malignant brain tumors
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Description
Explore the complexities of the nervous system, including its coordination with the endocrine system and the roles of the central and peripheral nervous systems. This quiz covers how the brain and spinal cord process information and command responses. Test your understanding of the fundamental tasks and subdivisions of the nervous system.